Glucose and xylose, derived from lignocellulose solids in the prior art, is customarily fermented to produce ethanol. Lignocellulose solids are selected from the group consisting of wood, waste paper and municipal solid waste including an individual or a combination including an individual or a combination thereof Hemicellulose, contained within lignocellulose solids, by hydrolysis in a first stage forms xylose which can be fermented to form ethanol. Xylose, within the first stage, upon additional reaction forms volatile furfural and lignocellulose solids containing cellulose and lignins substantially free of hemicellulose. The volatile furfural and water forms a vapor which is removed from the first stage. Hydrolysis of cellulose, contained in the lignocellulose solids, by a second stage, glucose is formed. Upon additional reaction of glucose hydroxymethylfurfural is formed. Fermentation of the mire containing glucose and hydroxymethylfurfural regards hydroxymethylfurfural as an unwanted constituent in the glucose mixture for fermentation. Hydroxymethylfurfural cannot be fermented to form ethanol by any known fermentation procedure.
It is therefore an object of this invention to obviate many of the limitations or disadvantages of the prior art.
The present concern is about producing hydroxymethylfurfural from lignocellulose solids containing cellulose.
A distinct object of this invention is to subject cellulose, contained in lignocellulose solids, to hydrolysis of the cellulose to form glucose and inevitably form hydroxymethylfurfural.
A crucial object of this invention is to remove hydroxymethylfurfural from solids containing lignins remaining from hydrolysis.
Another object of this invention is to avert fermentation of glucose and hydroxymethylfurfural.
Still another object of this invention is to extract solids, remaining from hydrolysis, to produce solids substantially free of acidic mixtures employed in hydrolysis. With the above and other objects in view, this invention relates to the novel features and alternatives and combinations presently described in the brief description of the invention.
A principle, applied in the present invention, employs acidic hydrolysis of hemicellulose and cellulose contained in lignocellulose solids. Hydrolysis of hemicellulose forms pentoses of several isomers. Upon dehydration reaction all pentoses form volatile furfural by the chemical formula, C5H10O5=C5H4O2+3H2O. Accordingly furfural is formed from pentoses derived from hemicellulose by hydrolysis. This chemical reaction is provided in Organic Chemistry, 1948, authored by Hill and Kelley, page 466.
Hydrolysis of cellulose contained in lignocellulose solids forms glucose. Upon dehydration reaction glucose forms volatile hydroxymethylfurfural by the chemical formula, C6H12O6=C6H6O3+3H2O. This chemical reaction is implied in Organic Chemistry, op. cit., page 480. Accordingly hydroxymethylfurfural is formed from glucose derived from cellulose by hydrolysis. HMF is the customary abbreviation for hydroxymethylfurfural Aqueous acidic solution employed for hydrolysis becomes diluted from water, upon dehydration to form furfural and HMF from sugars. Upon separation of diluted aqueous acidic solution, furfural, and HMF from hydrolysis surroundings, the diluted aqueous acidic solution can have water removed by miscellaneous methods, including vaporization. Conceivably the method of humidifying air with water to remove water from the diluted aqueous acidic solution is one such method. The method of humidifying air with water, disclosed by Brown, et. al, in Unit Operations, 1950, pages 542-543 and page 548, is a method for removing water by transferring water to air and accordingly humidifying air.
The present invention, in its broadest aspect, is a method to produce hydroxymethylfurfural by providing lignocellulose solids containing lignins, hemicellulose and cellulose to a vessel for hydrolysis. Hemicellulose, contained in the lignocellulose solids, is hydrolyzed to form pentoses which are converted to furfural and water.
Cellulose, contained in the lignocellulose solids, is subjected to hydrolysis to produce glucose from hydrolysis of cellulose. Upon continued exposure to hydrolysis the glucose is converted to hydroxymethylfurfural and water. Solids, remaining from hydrolysis, are removed from the vessel employed for hydrolysis and are filtered to produce a filtrate containing an aqueous acidic solution for reuse for hydrolysis. The filtered solids are extracted with water to remove aqueous acidic solution and form an extractate containing dilute aqueous acidic solution. Hydroxymethylfurfural, furfural and dilute aqueous acidic solution contained in the vessel employed for hydrolysis, is removed from the vessel followed by separation of the dilute aqueous acidic solution. Dilute solution of aqueous acidic solution is combined with the extactate and is treated to remove water from the aqueous acidic solution and then the aqueous acidic solution is recycled to the vessel for employment of hydrolysis. Thus hydroxymethylfurfural and furfural and separated from aqueous acidic solution to become liquid fuels derived from lignocellulose solids.
Characteristics of the invention include;
Production of furfural from hemicellulose contained in lignocellulose solids.
Production of hydroxymethylfurfural from cellulose contained in lignocellulose solids.
Removal of lignocellulose solids, containing lignins, from the vessel utilized for hydrolysis.
Filtering removed solids containing lignins.
Filtered solids are extracted by water to produce solids substantially free of aqueous acidic solution.
Extractate contains aqueous acidic solution and is recycled to be utilized for hydrolysis.
Liquid fuels are derived from lignocellulose solids without fermentation.